1. Field of the Invention
The present invention relates generally to reusable pallet systems and, more specifically, to improved covers for palletized loads as well as the combination of such covers with pallets including retractable belt systems.
2. Description of the Prior Art
Numerous patents disclosing pallets and various tie down devices were noted in a preliminary search directed to the subject matter of this invention. They are U.S. Pat. Nos. 2,442,266; 2,830,783; 3,416,762; 3,467,999; 3,685,799; 4,008,669; 4,050,664; 4,085,846; 4,227,286; 4,290,369; 4,305,505; 4,358,232; 4,367,572; 4,428,306; 4,569,108; 4,579,489; 4,604,014; 4,842,236; 4,887,731; 4,913,608; 4,995,525; 5,026,230; 5,035,558; 5,046,434; 5,063,641; 5,123,541; 5,173,996; and 5,197,396.
Pallets and pallet systems comprising pallets and load covers are well known and are widely used today for shipping a myriad of different items. Loads are secured to pallets in a variety of different ways. It is a fairly common practice today to position a load on a pallet and shrink wrap the load and pallet together to unitize the load and pallet. Some pallet loads are placed on pallets and not secured to the pallet, other than by gravity.
In the automotive industry, which is increasingly interested in recycling shipping materials including pallets, durable, reusable pallets have been combined with durable, reusable palletized load covers to reduce waste associated with the previously mentioned load securement means. Heretofore, such pallets covers have been secured to the pallets with seat belts. Specifically, with reference to FIG. 9 of the drawings, a pallet, indicated generally at 900, has a plurality of corner feet 902 and side feet 904. Each side foot 904 houses a conventional seat belt retractor mechanism (illustrated in FIG. 10 and discussed below in connection therewith) from which a conventional, virtually non-elastic, seat belt 906 extends through an opening, indicated at 908, in each of the side feet 904. A conventional male seat belt buckle 910 is securely connected to a distal end 912 of the belt in a conventional manner.
A conventional palletized load cover is indicated generally at 914. Four female seat belt buckles 916 are secured to the cover 914 with threaded fasteners 918. The combination consisting of the pallet 900 and cover 914 are available commercially from Robinson Industries. A belted pallet is also available from Penda Corporation. The combination of the cover 914 and the pallet 900 is used to secure a pallet load, indicated at L, as follows. The load L is positioned on the pallet 900, as shown in FIG. 9. One of the seat belts 906 is withdrawn from a seat belt retractor mechanism in one of the side feet 904, as indicated by arrow 920 as far as necessary in order to insert and lock the male buckle 910 in the female buckle 916. This procedure is repeated with the remaining three belts 906 until all of the male buckles 910 are locked into the female buckles 916. The belts 906 are cinched downwardly, towards the side feet 904, so that slack in the belts 906 can be taken up or rewound onto the associated retractor mechanism. As discussed below, such retractor mechanisms typically have light duty springs which retract the belt, but only when the belts are under virtually no tension. As the belts 906 retract, a conventional pawl and ratchet assembly (described below in connection with FIG. 10) permits the belts 906 to be retracted but prevents the belts 906 from being withdrawn from the retractor mechanism more than about one quarter of an inch. This procedure will tighten the belts 906 somewhat, but experience has proven that an unacceptable amount of slack remains in the belts because of deficiencies inherent in the system described above.
Part of the problem with the system described above can be attributed to the belt retractors which are housed in the side feet 904 of the pallet 900. Such a retractor is illustrated in FIG. 10 and is indicated generally by reference number 934. The retractor 934 comprises a housing 936 which includes an integral depending mounting flange 938 for securing the retractor 934, for example, inside a side foot 904 of a pallet 900 (FIG. 9). A belt 928 is wound about a rotatably mounted spool (not shown) in the retractor 934 (FIG. 10). A retractor spring 940 is connected to the spool in a known fashion so that can rotate the spool to rewind the belt 928. The spring, in conventional retractors, applies very little torque to the spool so that the belt will rewind only when there is virtually no unwinding tension applied to the belt 928. The retractor 934 includes a conventional ratchet wheel 942 and a pawl 944 which cooperate in a known fashion so that:
the belt 928 may be entirely or partially unwound from the spool; PA1 when a given portion of the belt 928 has been unwound and the belt is allowed to go slack, the pawl 944 becomes operable to engage the ratchet wheel 942 to prevent further unwinding of the belt 928 and, with the given portion of the belt unwound, the belt 928, if slack, will rewind on the spool under the action of the retractor spring 940 but the ratchet wheel 942 and the pawl 944 prevent unwinding of the belt 928 more than about one quarter of one inch; and PA1 when all or most of the belt 928 has been rewound onto the spool, the pawl 944 is rendered inoperable to prevent unwinding of the belt 928.
In the context of the pallet 900 and load cover 914 (FIG. 9), the retractor 934, and specifically the retractor spring 940, are simply inadequate to lock the belt 928 against unwinding with sufficient tautness in the belt 928 to properly secure the load L between the pallet 900 and the cover 914. Accordingly, there remains a need for a system for securing a palletized load cover to a pallet so that a load carried on the pallet is held tight and fast to the pallet.